Governments are currently concerned with the high incidence of obesity (and lesser degrees of weight gain) in populations, since they represent a known risk-factor for coronary heart disease, hypertension and diabetes. Besides dietary modification, the main thrust of treatment and weight maintenance after weight loss is physical exercise. It is now suggested by experts that diet alone is insufficient in the long term in maintaining weight loss without altering lifestyle, in particular the taking of more exercise. However one of the problems overweight people experience is that they find physical activity tiring and are easily fatigued. There is a need for a regime which will make obese people less fatigued so that they can exercise for longer periods, burn up more calories and lose more weight, or maintain their weight better after weight loss.
Moreover, in the last few years there has been considerable interest among athletes in creatine, which occurs abundantly in skeletal muscle. Creatine plays a pivotal role in the regulation and homeostasis of skeletal muscle energy metabolism and it is now generally accepted that the maintenance of phospho-creatine availability is important to the continuation of muscle force production. Although creatine synthesis occurs in the liver, kidney and pancreas it has been known for sometime that the oral ingestion of creatine will add to the whole body creatine pool, and it has been shown that the ingestion of 20 to 30 g creatine per day for several days can lead to a greater than 20% increase in human skeletal muscle total creatine content. Thus WO94/02127 discloses the administration of creatine in amounts of at least 15 g (or 0.2-0.4 g/kg body weight) per day, for at least 2 days, for increasing muscular strength.
In fact, it was subsequently found that after several days of supplementation (20 g per day) with creatine it takes no more than 2 to 3 g per day to maintain the saturation of body stores. Creatine supplementation in an appropriate dose can provide improvements to athletes involved in explosive events, which include all events lasting from a few seconds to a few minutes (such as sprinting, swimming, weight-lifting etc.). Endurance performance in events lasting longer than about 30 minutes appears to be unaffected by creatine supplementation. Creatine is a normal food component and is not a drug and its use is not contrary to official regulations. The biggest benefits of supplementation can be experienced by vegetarians or those who eat no meat or fish since these people tend to have low muscular creatine content.
Over the last few years there has been considerable interest in the use of isotonic drinks for people indulging in physical exercise. Human body fluids comprise water and substances dissolved therein, such as mineral salts known as electrolytes. These enable electrical impulses to stimulate muscle action. Isotonic drinks replace essential electrolytes lost in sweat during and/or after exercise. The term isotonic is applied to drinks containing the same concentration of minerals as in body fluids and in which the osmotic pressure is the same as that exerted by human body fluids. The most important electrolytes used in isotonic drinks are sodium, chloride, potassium, calcium, magnesium and phosphorus. Isotonic drinks can be made already diluted with water or conveniently packaged in sachets or cans as a powder which can then be mixed with still or carbonated water to give a refreshing flavoured drink of, for instance, a citrus flavour.
It is well known that creatine is unstable in aqueous solutions at acid or neutral pH, and is converted into the related compound creatinine. This is highly significant as creatinine has no muscle performance-enhancing effect and is excreted from the human body as a waste product in urine. In view of the foregoing, EP 0 669 083 teaches that aqueous drinks for human consumption comprising creatine must be weakly alkaline, in order to prevent the conversion of creatine into creatinine, and this has become the generally accepted opinion.